Hydrogen sulfide ameliorates chronic renal failure in rats by inhibiting apoptosis and inflammation through ROS/MAPK and NF-κB signaling pathways

Adenine-induced animal model of chronic kidney disease: current applications and future perspectives

Chronic kidney disease (CKD) with high morbidity and mortality all over the world is characterized by decreased kidney function, a condition which can result from numerous risk factors, including diabetes, hypertension and obesity. Despite significant advances in our understanding of the pathogenesis of CKD, there are still no treatments that can effectively combat CKD, which underscores the urgent need for further study into the pathological mechanisms underlying this condition. In this regard, animal models of CKD are indispensable. This article reviews a widely used animal model of CKD, which is induced by adenine. While a physiologic dose of adenine is beneficial in terms of biological activity, a high dose of adenine is known to induce renal disease in the organism. Following a brief description of the procedure for disease induction by adenine, major mechanisms of adenine-induced CKD are then reviewed, including inflammation, oxidative stress, programmed cell death, metabolic disorders, and fibrillation. Finally, the application and future perspective of this adenine-induced CKD model as a platform for testing the efficacy of a variety of therapeutic approaches is also discussed. Given the simplicity and reproducibility of this animal model, it remains a valuable tool for studying the pathological mechanisms of CKD and identifying therapeutic targets to fight CKD.

Potential protective effects of Acacia nilotica (L.) against gentamicin - induced nephrotoxicity by suppressing renal redox imbalance, inflammatory stress and caspase-dependent apoptosis in Wistar rats

Gentamicin-induced nephrotoxicity limits its therapeutic use as an effective aminoglycoside. Herbal drugs have a distinct place in the world of pharmaceuticals since they are safe, effective, and cost-efficient. Acacia nilotica (L.) has long been recognized for its antihypertensive, antioxidant, anti-inflammatory, and antiplatelet aggregatory benefits in traditional medicine. Still, the protective effect of Acacia nilotica on gentamicin-induced nephrotoxicity is still unknown. Thus, the goal of this research was to examine the protection of ethanolic extract of Acacia nilotica (ANE) against nephrotoxicity triggered by Gentamicin.

Thirty-six rats were randomly divided into six groups containing six rats in each group. The distilled water were given in control group. The rats in groups two and three were administered metformin and gentamicin respectively. In groups five and six, rats were administered ANE at doses of 100 and 200 mg/kg. Ten days of daily treatments were given. The urea, creatinine, uric acid, and LDH levels were analyzed on serum, whereas histological evaluation, MDA, GSH, SOD, CAT, TNF-α, IL-6, and caspase-3, were performed on kidney tissue on day 11. The gentamicin-treated group exhibited a significantly elevated MDA, and lower levels of antioxidant enzymes. Kidney function markers, inflammatory markers and caspase-3 expression were significantly elevated in the gentamicin-treated group. ANE significantly restored kidney function biomarkers, upregulated biochemical levels, inhibited TNF-α, caspase-3, cytokine expression, and reduced histological lesions.

In conclusion, ANE has the ability to prevent gentamicin-induced nephrotoxicity and reduce nephrotoxic damage. As such, it may represent an effective therapy for patients receiving gentamicin treatment.

Momordica cochinchinensis extract alleviates oxidative stress and skin damage caused by fine particulate matter

Momordica cochinchinensis (MC), commonly known as gac fruit, is a tropical fruit rich in antioxidants and bioactive compounds. This research aimed to elucidate the effect of MC on apoptosis induced by fine particulate matter with a diameter of less than 10 μm (< PM10) in epidermal keratinocyte HaCaT cells. We found that PM10 significantly diminish the viability of HaCaT cells through cytotoxic mechanisms. However, the treatment with MC at a concentration of 10 μg/mL notably restored the cellular viability decreased by PM10. MC reduced the activation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) by mainly preventing the generation of reactive oxygen species (ROS) in HaCaT cells subjected to PM10. Furthermore, MC exhibited a regulatory effect on the expression of genes associated with apoptosis, including B-Cell Lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax), and cleaved caspase-3 by inhibiting the activation of the transcription factor nuclear factor-kappa B (NF-κB). These findings demonstrate that MC aids in neutralizing the apoptotic signaling pathway of free radicals produced by environmental pollutants such as PM10, which have the potential to damage skin cells and accelerate the aging process.

The functions of hydrogen sulfide on the urogenital system of both males and females: from inception to the present

Hydrogen sulfide (H2S) is known as a chemical gas in nature with both enzymatic and non-enzymatic biosynthesis in different human organs. A couple of studies have demonstrated the function of H2S in regulating the homeostasis of the human body. Additionally, they have shown its synthesis, measurement, chemistry, protective effects, and interaction in various aspects of scientific evidence. Furthermore, many researches have demonstrated the beneficial impacts of H2S on genital organs and systems. According to various studies, it is recognized that H2S-producing enzymes and the endogenous production of H2S are expressed in male and female reproductive systems in different mammalian species. The main goal of this comprehensive review is to assess the potential therapeutic impacts of this gasotransmitter in the male and female urogenital system and find underlying mechanisms of this agent. This narrative review investigated the articles that were published from the 1970s to 2022. The review's primary focus is the impacts of H2S on the male and female urogenital system. Medline, CINAHL, PubMed, and Google scholar databases were searched. Keywords used in this review were "Hydrogen sulfide," "H2S," "urogenital system," and "urogenital tract". Numerous studies have demonstrated the therapeutic and protective effects of sodium hydrosulfide (Na-HS) as an H2S donor on male and female infertility disorders. Furthermore, it has been observed that H2S plays a significant role in improving different diseases such as ameliorating sperm parameters. The specific localization of H2S enzymes in the urogenital system provides an excellent opportunity to comprehend its function and role in various disorders related to this system. It is noteworthy that H2S has been demonstrated to be produced in endocrine organs and exhibit diverse activities. Moreover, it is important to recognize that alterations in H2S biosynthesis are closely linked to endocrine disorders. Therefore, hormones can be pivotal in regulating H2S production, and H2S synthesis pathways may aid in establishing novel therapeutic strategies. H2S possesses pharmacological effects on essential disorders, such as anti-inflammation, anti-apoptosis, and anti-oxidant activities, which render it a valuable therapeutic agent for human urogenital disease. Furthermore, this agent shows promise in ameliorating the detrimental effects of various male and female diseases. Despite the limited clinical research, studies have demonstrated that applying H2S as an anti-oxidant source could ameliorate adverse effects of different conditions in the urogenital system. More clinical studies are required to confirm the role of this component in clinical settings.

H2S-Releasing Versatile Montmorillonite Nanoformulation Trilogically Renovates the Gut Microenvironment for Inflammatory Bowel Disease Modulation

Abnormal activation of the intestinal mucosal immune system, resulting from damage to the intestinal mucosal barrier and extensive invasion by pathogens, contributes to the pathogenesis of inflammatory bowel disease (IBD). Current first-line treatments for IBD have limited efficacy and significant side effects. An innovative H2S-releasing montmorillonite nanoformulation (DPs@MMT) capable of remodeling intestinal mucosal immune homeostasis, repairing the mucosal barrier, and modulating gut microbiota is developed by electrostatically adsorbing diallyl trisulfide-loaded peptide dendrimer nanogels (DATS@PDNs, abbreviated as DPs) onto the montmorillonite (MMT) surface. Upon rectal administration, DPs@MMT specifically binds to and covers the damaged mucosa, promoting the accumulation and subsequent internalization of DPs by activated immune cells in the IBD site. DPs release H2S intracellularly in response to glutathione, initiating multiple therapeutic effects. In vitro and in vivo studies have shown that DPs@MMT effectively alleviates colitis by eliminating reactive oxygen species (ROS), inhibiting inflammation, repairing the mucosal barrier, and eradicating pathogens. RNA sequencing revealed that DPs@MMT exerts significant immunoregulatory and mucosal barrier repair effects, by activating pathways such as Nrf2/HO-1, PI3K-AKT, and RAS/MAPK/AP-1, and inhibiting the p38/ERK MAPK, p65 NF-κB, and JAK-STAT3 pathways, as well as glycolysis. 16S rRNA sequencing demonstrated that DPs@MMT remodels the gut microbiota by eliminating pathogens and increasing probiotics. This study develops a promising nanoformulation for IBD management.

Biochar Decreases Fertilizer Leaching and Promotes Miscanthus Growth in Saline-Alkaline Soil

Biochar has been widely reported to improve soil conditions and affect plant growth. However, its effectiveness is limited by soil type and production technology. Considering the application effect of biochar in saline alkali soil, there is currently a lack of in-depth mechanism explanations in the research. Therefore, we designed an experiment to explore the effect of biochar on plant growth in saline alkali soil and conducted soil column experiments in a greenhouse environment using composite inorganic fertilizer (NPK). The results showed that biochar significantly affected the distribution of soil nutrient content at different depths, with a significant increase in fertility levels in the surface and middle layers and a decrease in fertility levels in deep soils. Compared to using fertilizers alone, the combined use of biochar and fertilizers further expands the enrichment effect and significantly reduces the leaching of fertilizers into deeper layers. At the same time, the application of biochar also improved soil properties, including an increase in electrical conductivity and organic matter content, as well as an increase in soil enzyme activity. On the other hand, the application of biochar also increases the activity of antioxidant enzymes and the content of osmoregulation substances in plants, reducing the environmental stress that plants are subjected to. Therefore, our results indicate that biochar can reduce the leaching of fertilizers into deep soil layers, improve soil properties, and promotes the growth of Miscanthus in saline alkali soils.

The Role of Gasotransmitter-Dependent Signaling Mechanisms in Apoptotic Cell Death in Cardiovascular, Rheumatic, Kidney, and Neurodegenerative Diseases and Mental Disorders

Cardiovascular, rheumatic, kidney, and neurodegenerative diseases and mental disorders are a common cause of deterioration in the quality of life up to severe disability and death worldwide. Many pathological conditions, including this group of diseases, are based on increased cell death through apoptosis. It is known that this process is associated with signaling pathways controlled by a group of gaseous signaling molecules called gasotransmitters. They are unique messengers that can control the process of apoptosis at different stages of its implementation. However, their role in the regulation of apoptotic signaling in these pathological conditions is often controversial and not completely clear. This review analyzes the role of nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H₂S), and sulfur dioxide (SO₂) in apoptotic cell death in cardiovascular, rheumatic, kidney, and neurodegenerative diseases. The signaling processes involved in apoptosis in schizophrenia, bipolar, depressive, and anxiety disorders are also considered. The role of gasotransmitters in apoptosis in these diseases is largely determined by cell specificity and concentration. NO has the greatest dualism; scales are more prone to apoptosis. At the same time, CO, H₂S, and SO₂ are more involved in cytoprotective processes.

Proteomic landscape of the extracellular matrix in the fibrotic kidney

The extracellular matrix (ECM) is a complex three-dimensional network of proteins surrounding cells, forming a niche that controls cell adhesion, proliferation, migration and differentiation. The ECM network provides an architectural scaffold for surrounding cells and undergoes dynamic changes in composition and contents during the evolution of chronic kidney disease (CKD). Here, we unveiled the proteomic landscape of the ECM by delineating proteome-wide and ECM-specific alterations in normal and fibrotic kidneys. Decellularized kidney tissue scaffolds were made and subjected to proteomic profiling by liquid chromatography with tandem mass spectrometry. A total of 172 differentially expressed proteins were identified in these scaffolds from mice with CKD. Through bioinformatics analysis and experimental validation, we identified a core set of nine signature proteins, which could play a role in establishing an oxidatively stressed, profibrotic, proinflammatory and antiangiogenetic microenvironment. Among these nine proteins, glutathione peroxidase 3 (GPX3) was the only protein with downregulated expression during CKD. Knockdown of GPX3 in vivo augmented ECM expression and aggravated kidney fibrotic lesions after obstructive injury. Transcriptomic profiling revealed that GPX3 depletion resulted in an altered expression of the genes enriched in hypoxia pathway. Knockdown of GPX3 induced NADPH oxidase 2 expression, promoted kidney generation of reactive oxygen species and activated p38 mitogen-activated protein kinase. Conversely, overexpression of exogenous GPX3 alleviated kidney fibrosis, inhibited NADPH oxidase 2 and p38 mitogen-activated protein kinase. These findings suggest that oxidative stress is a pivotal element of the fibrogenic microenvironment. Thus, our studies represent a comprehensive proteomic characterization of the ECM in the fibrotic kidney and provide novel insights into molecular composition of the fibrogenic microenvironment.

Diosmin Mitigates Gentamicin-Induced Nephrotoxicity in Rats: Insights on miR-21 and -155 Expression, Nrf2/HO-1 and p38-MAPK/NF-κB Pathways

Gentamicin (GNT) is the most frequently used aminoglycoside. However, its therapeutic efficacy is limited due to nephrotoxicity. Thus, the potential anticipatory effect of Diosmin (DIOS) against GNT-prompted kidney damage in rats together with the putative nephroprotective pathways were scrutinized. Four groups of rats were used: (1) control; (2) GNT only; (3) GNT plus DIOS; and (4) DIOS only. Nephrotoxicity was elucidated, and the microRNA-21 (miR-21) and microRNA-155 (miR-155) expression and Nrf2/HO-1 and p38-MAPK/NF-κB pathways were assessed. GNT provoked an upsurge in the relative kidney weight and serum level of urea, creatinine, and KIM-1. The MDA level was markedly boosted, with a decline in the level of TAC, SOD, HO-1, and Nrf2 expression in the renal tissue. Additionally, GNT exhibited a notable amplification in TNF-α, IL-1β, NF-κB p65, and p38-MAPK kidney levels. Moreover, caspase-3 and BAX expression were elevated, whereas the Bcl-2 level was reduced. Furthermore, GNT resulted in the down-regulation of miR-21 expression along with an up-regulation of the miR-155 expression. Histological examination revealed inflammation, degradation, and necrosis. GNT-provoked pathological abnormalities were reversed by DIOS treatment, which restored normal kidney architecture. Hence, regulating miR-21 and -155 expression and modulating Nrf2/HO-1 and p38-MAPK/NF-κB pathways could take a vital part in mediating the reno-protective effect of DIOS.

The roles of hydrogen sulfide in renal physiology and disease states

Hydrogen sulfide (H₂S), an endogenous gaseous signaling transmitter, has gained recognition for its physiological effects. In this review, we aim to summarize and discuss existing studies about the roles of H₂S in renal functions and renal disease as well as the underlying mechanisms. H₂S is mainly produced by four pathways, and the kidneys are major H₂S–producing organs. Previous studies have shown that H₂S can impact multiple signaling pathways via sulfhydration. In renal physiology, H₂S promotes kidney excretion, regulates renin release and increases ATP production as a sensor for oxygen. H₂S is also involved in the development of kidney disease. H₂S has been implicated in renal ischemia/reperfusion and cisplatin–and sepsis–induced kidney disease. In chronic kidney diseases, especially diabetic nephropathy, hypertensive nephropathy and obstructive kidney disease, H₂S attenuates disease progression by regulating oxidative stress, inflammation and the renin–angiotensin–aldosterone system. Despite accumulating evidence from experimental studies suggesting the potential roles of H₂S donors in the treatment of kidney disease, these results need further clinical translation. Therefore, expanding the understanding of H₂S can not only promote our further understanding of renal physiology but also lay a foundation for transforming H₂S into a target for specific kidney diseases.

The Expression Levels of SARS-CoV-2 Infection-Mediating Molecules Promoted by Interferon-γ and Tumor Necrosis Factor-α Are Downregulated by Hydrogen Sulfide

Autoimmune thyroid diseases (AITDs), which include Hashimoto’s thyroiditis (HT) and Graves’ disease (GD), have a higher prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the literature. The effects of AITD-associated cytokines on SARS-CoV-2 infection-mediating molecule levels might be involved in the pathogenesis of susceptibility. We speculated that hydrogen sulfide (H2S) might attenuate this process since H2S has antiviral effects. Using immunohistochemistry, we found that angiotensin-converting enzyme-II (ACE2) expression was higher in the HT group and neuropilin 1 (NRP1) expression was higher in HT and GD groups than in the normal group, while transmembrane protease serine type 2 (TMPRSS2) expression was lower in HT and GD groups. When culturing primary thyrocytes with cytokines or sodium hydrosulfide (NaHS) plus cytokines, we found that ACE2 and NRP1 mRNA levels were upregulated while TMPRSS2 levels were downregulated by interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α). After pretreatment with NaHS in thyrocytes, ACE2 and NRP1 expression were downregulated compared to IFN-γ or TNF-α treatment, and NaHS had no effect on TMPRSS2 expression. Our findings suggested that IFN-γ and TNF-α, which are elevated in AITDs, promoted ACE2 and NRP1 expression and inhibited TMPRSS2 expression. H2S might protect against SARS-CoV-2 infection by downregulating ACE2 and NRP1 levels.

HA-ADT suppresses esophageal squamous cell carcinoma progression via apoptosis promotion and autophagy inhibition

Esophageal squamous cell carcinoma (ESCC) is a major cause of cancer-related deaths. We have previously connected a non-sulfated glycosaminoglycan, hyaluronic acid (HA), with a common hydrogen sulfide (H₂S) donor, 5-(4-hydroxyphenyl)-3H-1,2-dithiol-3-thione (ADT-OH), to reconstruct a novel conjugate, HA-ADT. In this study, we determined the effect of HA-ADT on the growth of ESCC. Our data suggested that HA-ADT exerted more potent effects than sodium hydrosulfide (NaHS, a fast H₂S-releasing donor) and morpholin-4-ium (4-methoxyphenyl)-morpholin-4-ylsulfanylidenesulfido-λ5-phosphane (GYY4137, a slow H₂S-releasing donor) on inhibiting the viability, proliferation, migration, and invasion of human ESCC cells. HA-ADT increased apoptosis by suppressing the protein expressions of phospho (p)-Ser473-protein kinase B (PKB/AKT), p-Tyr199/Tyr458-phosphatidylinositol 3-kinase (PI3K), and p-Ser2448-mammalian target of rapamycin (mTOR), but suppressed autophagy through the inhibition of the protein levels of p-Ser552-β-catenin, p-Ser9-glycogen synthase kinase-3β (GSK-3β), and Wnt3a in human ESCC cells. In addition, HA-ADT was more effective in terms of the growth inhibition of human ESCC xenograft tumor than NaHS and GYY4137. In conclusion, HA-ADT can suppress ESCC progression via apoptosis promotion and autophagy inhibition. HA-ADT might be efficacious for the treatment of cancer.

Grifola frondosa Extract Containing Bioactive Components Blocks Skin Fibroblastic Inflammation and Cytotoxicity Caused by Endocrine Disrupting Chemical, Bisphenol A

Grifola frondosa (GF), a species of Basidiomycotina, is widely distributed across Asia and has been used as an immunomodulatory, anti-bacterial, and anti-cancer agent. In the present study, the pharmacological activity of the GF extract against an ecotoxicological industrial chemical, bisphenol A (BPA) in normal human dermal fibroblasts (NHDFs), was investigated. GF extract containing naringin, hesperidin, chlorogenic acid, and kaempferol showed an inhibitory effect on cell death and inflammation induced by BPA in the NHDFs. For the cell death caused by BPA, GF extract inhibited the production of reactive oxygen species responsible for the unique activation of the extracellular signal-regulated kinase. In addition, GF extract attenuated the expression of apoptosis-related proteins (Bax, Bcl-2, and cleaved caspase-3) and the pro-inflammatory cytokine IL-1β by the suppression of the redox-sensitive transcription factor, nuclear factor-kappa B (NF-κB) in BPA-treated NHDFs. For the inflammation triggered by BPA, GF extract blocked the inflammasome-mediated caspase-1 activation that leads to the secretion of IL-1β protein. These results indicate that the GF extract is a functional antioxidant that prevents skin fibroblastic pyroptosis induced by BPA.

Polyphenols target miRNAs as a therapeutic strategy for diabetic complications

MiRNAs are a large group of non-coding RNAs which participate in different cellular pathways like inflammation and oxidation through transcriptional, post-transcriptional, and epigenetic regulation. In the post-transcriptional regulation, miRNA interacts with the 3'-UTR of mRNAs and prevents their translation. This prevention or dysregulation can be a cause of pathological conditions like diabetic complications. A huge number of studies have revealed the association between miRNAs and diabetic complications, including diabetic nephropathy, cardiomyopathy, neuropathy, retinopathy, and delayed wound healing. To address this issue, recent studies have focused on the use of polyphenols as selective and safe drugs in the treatment of diabetes complications. In this article, we will review the involvement of miRNAs in diabetic complications' occurrence or development. Finally, we will review the latest findings on targeting miRNAs by polyphenols like curcumin, resveratrol, and quercetin for diabetic complications therapy.

Allyl methyl trisulfide protected against LPS-induced acute lung injury in mice via inhibition of the NF-κB and MAPK pathways

Allyl methyl trisulfide (AMTS) is one major lipid-soluble organosulfur compound of garlic. Previous studies have reported the potential therapeutic effect of garlic on acute lung injury (ALI) or its severe condition acute respiratory distress syndrome (ARDS), but the specific substances that exert the regulatory effects are still unclear. In this study, we investigate the protective effects of AMTS on lipopolysaccharide (LPS)-induced ALI mice and explored the underlying mechanisms. In vivo experiments, ICR mice were pretreated with 25–100 mg/kg AMTS for 7 days and followed by intratracheal instillation of LPS (1.5 mg/kg). The results showed that AMTS significantly attenuated LPS-induced deterioration of lung pathology, demonstrated by ameliorative edema and protein leakage, and improved pulmonary histopathological morphology. Meanwhile, the expression of inflammatory mediators and the infiltration of inflammation-regulation cells induced by LPS were also inhibited. In vitro experiments also revealed that AMTS could alleviate inflammation response and inhibit the exaggeration of macrophage M1 polarization in LPS-induced RAW264.7 cells. Mechanistically, we identified that AMTS treatment could attenuate the LPS-induced elevation of protein expression of p-IκBα, nuclear NF-κB-p65, COX2, iNOS, p-P38, p-ERK1/2, and p-JNK. Collectively, these data suggest that AMTS could attenuate LPS-induced ALI and the molecular mechanisms should be related to the suppression of the NF-κB and MAPKs pathways.

Effects of Uremic Clearance Granules on p38 MAPK/NF-κB Signaling Pathway, Microbial and Metabolic Profiles in End-Stage Renal Disease Rats Receiving Peritoneal Dialysis

Background

Methods

Results

Conclusion

Recent Advances in Molecular Research on Hydrogen Sulfide (H2S) Role in Diabetes Mellitus (DM)-A Systematic Review

Abundant experimental data suggest that hydrogen sulfide (H₂S) is related to the pathophysiology of Diabetes Mellitus (DM). Multiple molecular mechanisms, including receptors, membrane ion channels, signalingmolecules, enzymes, and transcription factors, are known to be responsible for the H₂S biological actions; however, H₂S is not fully documented as a gaseous signaling molecule interfering with DM and vascular-linked pathology. In recent decades, multiple approaches regarding therapeutic exploitation of H₂S have been identified, either based on H₂S exogenous apport or on its modulated endogenous biosynthesis. This paper aims to synthesize and systematize, as comprehensively as possible, the recent literature-related data regarding the therapeutic/rehabilitative role of H₂S in DM. This review was conducted following the “Preferred reporting items for systematic reviews and meta-analyses” (PRISMA) methodology, interrogating five international medically renowned databases by specific keyword combinations/“syntaxes” used contextually, over the last five years (2017–2021). The respective search/filtered and selection methodology we applied has identified, in the first step, 212 articles. After deploying the next specific quest steps, 51 unique published papers qualified for minute analysis resulted. To these bibliographic resources obtained through the PRISMA methodology, in order to have the best available information coverage, we added 86 papers that were freely found by a direct internet search. Finally, we selected for a connected meta-analysis eight relevant reports that included 1237 human subjects elicited from clinical trial registration platforms. Numerous H₂S releasing/stimulating compounds have been produced, some being used in experimental models. However, very few of them were further advanced in clinical studies, indicating that the development of H₂S as a therapeutic agent is still at the beginning.

Hydrogen Sulfide Biology and Its Role in Cancer

Hydrogen sulfide (H₂S) is an endogenous biologically active gas produced in mammalian tissues. It plays a very critical role in many pathophysiological processes in the body. It can be endogenously produced through many enzymes analogous to the cysteine family, while the exogenous source may involve inorganic sulfide salts. H₂S has recently been well investigated with regard to the onset of various carcinogenic diseases such as lung, breast, ovaries, colon cancer, and neurodegenerative disorders. H₂S is considered an oncogenic gas, and a potential therapeutic target for treating and diagnosing cancers, due to its role in mediating the development of tumorigenesis. Here in this review, an in-detail up-to-date explanation of the potential role of H₂S in different malignancies has been reported. The study summarizes the synthesis of H₂S, its roles, signaling routes, expressions, and H₂S release in various malignancies. Considering the critical importance of this active biological molecule, we believe this review in this esteemed journal will highlight the oncogenic role of H₂S in the scientific community.

Uremic Toxin Indoxyl Sulfate Impairs Hydrogen Sulfide Formation in Renal Tubular Cells

Hydrogen sulfide (H₂S) was the third gasotransmitter to be recognized as a cytoprotectant. A recent study demonstrated that exogenous supplementation of H₂S ameliorates functional insufficiency in chronic kidney disease (CKD). However, how the H₂S system is impaired by CKD has not been elucidated. The uremic toxin indoxyl sulfate (IS) is known to accumulate in CKD patients and harm the renal tubular cells. This study therefore treated the proximal tubular cells, LLC-PK₁, with IS to see how IS affects H₂S formation. Our results showed that H₂S release from LLC-PK₁ cells was markedly attenuated by IS when compared with control cells. The H₂S donors NaHS and GYY-4137 significantly attenuated IS-induced tubular damage, indicating that IS impairs H₂S formation. Interestingly, IS downregulated the H₂S-producing enzymes cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST), and these effects could be reversed by inhibition of the IS receptor, aryl hydrocarbon receptor (AhR). As transcription factor specificity protein 1 (Sp1) regulates the gene expression of H₂S-producing enzymes, we further showed that IS significantly decreased the DNA binding activity of Sp1 but not its protein expression. Blockade of AhR reversed low Sp1 activity caused by IS. Moreover, exogenous H₂S supplementation attenuated IS-mediated superoxide formation and depletion of the cellular glutathione content. These results clearly indicate that IS activates AhR, which then attenuates Sp1 function through the regulation of H₂S-producing enzyme expression. The attenuation of H₂S formation contributes to the low antioxidant defense of glutathione in uremic toxin-mediated oxidative stress, causing tubular cell damage.

Vasorelaxant Activity of AP39, a Mitochondria-Targeted H2S Donor, on Mouse Mesenteric Artery Rings In Vitro

Mitochondria-targeted hydrogen sulfide (H2S) donor compounds, such as compound AP39, supply H2S into the mitochondrial environment and have shown several beneficial in vitro and in vivo effects in cardiovascular conditions such as diabetes and hypertension. However, the study of their direct vascular effects has not been addressed to date. Thus, the objective of the present study was to analyze the effects and describe the mechanisms of action of AP39 on the in vitro vascular reactivity of mouse mesenteric artery. Protein and gene expressions of the H2S-producing enzymes (CBS, CSE, and 3MPST) were respectively analyzed by Western blot and qualitative RT-PCR, as well the in vitro production of H2S by mesenteric artery homogenates. Gene expression of CSE and 3MPST in the vessels has been evidenced by RT-PCR experiments, whereas the protein expression of all the three enzymes was demonstrated by Western blotting experiments. Nonselective inhibition of H2S-producing enzymes by AOAA abolished H2S production, whereas it was partially inhibited by PAG (a CSE selective inhibitor). Vasorelaxation promoted by AP39 and its H2S-releasing moiety (ADT-OH) were significantly reduced after endothelium removal, specifically dependent on NO-cGMP signaling and SKCa channel opening. Endogenous H2S seems to participate in the mechanism of action of AP39, and glibenclamide-induced KATP blockade did not affect the vasorelaxant response. Considering the results of the present study and the previously demonstrated antioxidant and bioenergetic effects of AP39, we conclude that mitochondria-targeted H2S donors may offer a new promising perspective in cardiovascular disease therapeutics.

Quercetin ameliorated remote myocardial injury induced by renal ischemia/reperfusion in rats: Role of Rho-kinase and hydrogen sulfide

AIMS

This study was designated to investigate the means through which quercetin confers its cardioprotective action against remote cardiomyopathy elicited by renal ischemia/reperfusion (I/R). Potential involvement of hydrogen sulfide (H₂S) and its related mechanisms were accentuated herein.

MAIN METHODS

In anesthetized male Wistar rats, renal I/R was induced by bilateral renal pedicles occlusion for 30 min (ischemia) followed by 24 h reperfusion. Quercetin (50 mg/kg, gavage) was administered at 5 h post reperfusion initiation and 2 h before euthanasia. Cystathionine β-synthase (CBS) inhibitor, amino-oxyacetic acid (AOAA; 10 mg/kg, i.p) was given 30 min prior to each quercetin dose.

KEY FINDINGS

Quercetin reversed renal I/R induced derangements; as quercetin administration improved renal function and reversed I/R induced histopathological changes in both myocardium and kidney. Further, quercetin enhanced renal CBS content/activity, while mitigated myocardial cystathionine ɤ-lyase (CSE) content/activity as well as myocardial H₂S. On the other hand, quercetin augmented myocardial nitric oxide (NO), nuclear factor erythroid 2-related factor 2 (Nrf2) and its nuclear trasnslocation, glutamate cysteine ligase (GCL), reduced glutathione (GSH) and peroxiredoxin-2 (Prx2), while further reduced lipid peroxidation measured as malondialdehyde (MDA) as well as nuclear factor-kappa B (NF-κB), caspase-3 content and activity, and Rho-kinase activity.

SIGNIFICANCE

Cardioprotective effects of quercetin may be mediated through regulation of Rho-kinase pathway and H₂S production.

High-dose versus low-dose iron sucrose in individuals undergoing maintenance haemodialysis: a retrospective study

BACKGROUND

Intravenous iron sucrose is becoming a prevailing treatment for individuals undergoing maintenance haemodialysis, but comparisons of dosing regimens are lacking. The aim of this retrospective review was to evaluate the safety and efficacy of proactively administered high-dose iron sucrose versus reactively administered low-dose iron sucrose in patients undergoing maintenance haemodialysis.

METHODS

We analysed the data of 1500 individuals with maintenance haemodialysis who were treated with either high-dose iron sucrose that was proactively administered (Group HD) or low-dose iron sucrose that was reactively administered (Group LD) at the First Affiliated Hospital of Chongqing Medical University from Jan 1, 2008, to Dec 31, 2020. The primary endpoints were the cumulative doses of iron and erythropoiesis-stimulating agent; the secondary endpoints were the events of nonfatal myocardial infarction, nonfatal stroke, hospitalization for heart failure, infection rate, and death from any cause.

RESULTS

Of the 2124 individuals, 624 individuals were excluded because they met one or more of the exclusion criteria, thus resulting in 1500 individuals who were eligible for inclusion in the study (Group HD, n = 760 and Group LD, n = 740). The median follow-up for the two cohorts was 32 months (range: 25-36). A significant median difference was detected in the monthly iron dose between the groups (1121 mg [range: 800-1274] in the HD group vs. 366 mg [range: 310-690] in the LD group; p < 0.05). The median dose of an erythropoiesis-stimulating agent was 26,323 IU/month (range: 17,596-44,712) in the HD group and 37,934 IU/month (range: 22,402-59,380) in the LD group (median difference: - 7901 IU/month; 95% CI: - 9632--5013; p = 0.000). A significant difference was detected in the secondary endpoints (266 events in 320 cases in the HD group vs. 344 events in 385 cases in the LD group) (HR: 0.62; 95% CI: 0.51-0.79; p < 0.001). A significant difference was not observed in death from any cause (HR: 0.57; 95% CI: 0.48-1.00; p = 0.361).

CONCLUSIONS

For individuals undergoing maintenance haemodialysis, high-dose iron sucrose that was proactively administered may be superior to low-dose iron sucrose that was reactively administered with low doses of erythropoiesis-stimulating agent.

Involvement of oxidative stress and toll-like receptor-4 signaling pathways in gentamicin-induced nephrotoxicity in male Sprague Dawley rats

Gentamicin (GM) is an antibiotic belonging to an aminoglycoside family that might induce nephrotoxicity in human and animal models via oxidative stress. Toll-like receptors (TLRs) are part of innate immune systems that participate in inflammatory responses. In this regard, we investigated the effect of GM on kidney functional and structural parameters, enzymatic antioxidant levels, and mRNA expression of TLR4 and IL6 in the rat kidney. Adult male Sprague Dawley rats were randomly divided into two groups (n = 10): Control and Gentamicin (100 mg/kg, i.p.). After ten days of GM administration, a blood sample was taken, and the kidneys were removed. The serum levels of creatinine (Cr) and blood urea nitrogen (BUN) were measured. Furthermore, the right kidney was preserved in formalin 10% for hematoxylin and eosin (H&E) staining, and the left kidney was kept at -80 °C for molecular and oxidative indexes analysis. Administration of GM caused tubular damages and functional disturbance. So that, Cr and BUN values in the GM group were higher than Control group. Furthermore, molecular findings showed upregulation of TLR4 and IL-6 mRNA expression in renal tissue of the GM-received group. In this study, superoxide dismutase (SOD) activity was slightly increased as a compensatory mechanism in response to elevated malondialdehyde (MDA) levels in the GM-treated group. On the other hand, the activity of catalase (CAT) and glutathione peroxidase (GPx) were significantly declined. Our results demonstrated that oxidative stress and subsequent TLR4 upregulation signaling pathways are involved in GM-induced nephrotoxicity.

Kaempferol Blocks the Skin Fibroblastic Interleukin 1β Expression and Cytotoxicity Induced by 12-O-tetradecanoylphorbol-13-acetate by Suppressing c-Jun N-terminal Kinase

Kaempferol, a bioflavonoid present in fruits and vegetables, has a variety of antioxidant and anti-inflammatory capacities, but the functional role of kaempferol in oxidative skin dermal damage has yet to be well studied. In this study, we examine the role of kaempferol during the inflammation and cell death caused by 12-O-tetradecanoylphorbol-13-acetate (TPA) in normal human dermal fibroblasts (NHDF). TPA (5 μM) significantly induced cytotoxicity of NHDF, where a robust increase in the interleukin (IL)-1β mRNA among the various pro-inflammatory cytokines. The skin fibroblastic cytotoxicity and IL-1β expression induced by TPA were significantly ameliorated by a treatment with 100 nM of kaempferol. Kaempferol blocked the production of the intracellular reactive oxygen species (ROS) responsible for the phosphorylation of c-Jun N-terminal kinase (JNK) induced by TPA. Interestingly, we found that kaempferol inhibited the phosphorylation of nuclear factor-kappa B (NF-κB) and the inhibitor NF-κB (IκBα), which are necessary for the expression of cleaved caspase-3 and the IL-1β secretion in TPA-treated NHDF. These results suggest that kaempferol is a functional agent that blocks the signaling cascade of the skin fibroblastic inflammatory response and cytotoxicity triggered by TPA.

Astaxanthin Inhibits Autophagic Cell Death Induced by Bisphenol A in Human Dermal Fibroblasts

Astaxanthin, a natural antioxidant carotenoid, is a nutrient with diverse health benefits, given that it decreases the risk of oxidative stress-related diseases. In the present study, we investigate the functional role of astaxanthin during autophagic cell death induced by the estrogenic endocrine-disrupting chemical bisphenol A (BPA) in normal human dermal fibroblasts (NHDF). BPA significantly induced apoptotic cell death and autophagy in NHDF. Autophagic cell death evoked by BPA was significantly restored upon a treatment with astaxanthin (10 μM) via the inhibition of intracellular reactive oxygen species (ROS) production. Astaxanthin inhibited the phosphorylation of extracellular signal-regulated kinases (ERK) stimulated by ROS production, but it did not influence the activation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) in BPA-treated NHDF. Astaxanthin abrogated the ERK-mediated activation of nuclear factor-kappa B (NF-κB), which is responsible for the mRNA expression of LC3-II, Beclin-1, Atg12, and Atg14 during apoptotic cell death induced by BPA. These results indicate that astaxanthin is a pharmacological and nutritional agent that blocks the skin fibroblastic autophagic cell death induced by BPA in human dermal fibroblasts.

Two-sided effects of prolonged hypoxia and sulfide exposure on juvenile ark shells (Anadara broughtonii)

Oxygen deficit and sulfide have been restrictive factors in mariculture zones. However, the adaptive mechanism in aquatic lives is still unclear. The commercial ark shells Anadara broughtonii were selected to test the tolerance and adaptive responses to prolonged and intermittent hypoxia with or without exogenous sulfide (mild, moderate, high) by evaluating their behavior, mortality, oxidative level, antioxidant responses, and the MAPK-mediated apoptosis in gills. The results indicated that the clams were tolerant to hypoxia and sulfide exposure but vulnerable during reoxygenation from the challenges. Even so, sulfide had remarkable effect on attenuating the accumulation of reactive oxygen species (ROS) and lipid peroxides caused by reoxygenation from prolonged hypoxia. The increase of glutathione level was probably as an early and primary protective response to prevent the expected reperfusion injury from reoxygenation. The challenges suppressed the oxidative level with a dose-dependent effect of sulfide, with an exception when exposed to mild sulfide. Synchronously, biphasic effects of exogenous sulfide on apoptotic cascade, which was induced by mild sulfide while it was inhibited by higher sulfide, were also detected in gills. The induced or inhibited apoptosis by hypoxia and sulfide kept to a typical ROS-MAPK-CASPASE cascade, desiderating further investigation.

Hydrogen sulfide in longevity and pathologies: Inconsistency is malodorous

Hydrogen sulfide (H₂S) is one of the biologically active gases (gasotransmitters), which plays an important role in various physiological processes and aging. Its production in the course of methionine and cysteine catabolism and its degradation are finely balanced, and impairment of H₂S homeostasis is associated with various pathologies. Despite the strong geroprotective action of exogenous H₂S in C. elegans, there are controversial effects of hydrogen sulfide and its donors on longevity in other models, as well as on stress resistance, age-related pathologies and aging processes, including regulation of senescence-associated secretory phenotype (SASP) and senescent cell anti-apoptotic pathways (SCAPs). Here we discuss that the translation potential of H₂S as a geroprotective compound is influenced by a multiplicity of its molecular targets, pleiotropic biological effects, and the overlapping ranges of toxic and beneficial doses. We also consider the challenges of the targeted delivery of H₂S at the required dose. Along with this, the complexity of determining the natural levels of H₂S in animal and human organs and their ambiguous correlations with longevity are reviewed.

The Role of Hydrogen Sulfide in Respiratory Diseases

Respiratory diseases are leading causes of death and disability around the globe, with a diverse range of health problems. Treatment of respiratory diseases and infections has been verified to be thought-provoking because of the increasing incidence and mortality rate. Hydrogen sulfide (H₂S) is one of the recognized gaseous transmitters involved in an extensive range of cellular functions, and physiological and pathological processes in a variety of diseases, including respiratory diseases. Recently, the therapeutic potential of H₂S for respiratory diseases has been widely investigated. H₂S plays a vital therapeutic role in obstructive respiratory disease, pulmonary fibrosis, emphysema, pancreatic inflammatory/respiratory lung injury, pulmonary inflammation, bronchial asthma and bronchiectasis. Although the therapeutic role of H₂S has been extensively studied in various respiratory diseases, a concrete literature review will have an extraordinary impact on future therapeutics. This review provides a comprehensive overview of the effective role of H₂S in respiratory diseases. Besides, we also summarized H₂S production in the lung and its metabolism processes in respiratory diseases.

Epigallocatechin-3-Gallate Alleviates High-Fat Diet-Induced Nonalcoholic Fatty Liver Disease via Inhibition of Apoptosis and Promotion of Autophagy through the ROS/MAPK Signaling Pathway

Nonalcoholic fatty liver disease (NAFLD) represents one of the most common chronic liver diseases in the world. It has been reported that epigallocatechin-3-gallate (EGCG) plays important biological and pharmacological roles in mammalian cells. Nevertheless, the mechanism underlying the beneficial effect of EGCG on the progression of NAFLD has not been fully elucidated. In the present study, the mechanisms of action of EGCG on the growth, apoptosis, and autophagy were examined using oleic acid- (OA-) treated liver cells and the high-fat diet- (HFD-) induced NAFLD mouse model. Administration of EGCG promoted the growth of OA-treated liver cells. EGCG could reduce mitochondrial-dependent apoptosis and increase autophagy possibly via the reactive oxygen species- (ROS-) mediated mitogen-activated protein kinase (MAPK) pathway in OA-treated liver cells. In line with in vitro findings, our in vivo study verified that treatment with EGCG attenuated HFD-induced NAFLD through reduction of apoptosis and promotion of autophagy. EGCG can alleviate HFD-induced NAFLD possibly by decreasing apoptosis and increasing autophagy via the ROS/MAPK pathway. EGCG may be a promising agent for the treatment of NAFLD.

Tart Cherry Extract Containing Chlorogenic Acid, Quercetin, and Kaempferol Inhibits the Mitochondrial Apoptotic Cell Death Elicited by Airborne PM10 in Human Epidermal Keratinocytes

Tart cherry (Prunus cerasus L.), a medicinal food containing high concentrations of phytochemicals, has a variety of antioxidant activities and health benefits. Here, we investigate the functional effect of tart cherry during apoptotic cell death elicited by airborne particulate matter with a diameter of <10 μm (PM₁₀) in human epidermal keratinocyte HaCaT cells. The PM₁₀ particles significantly induced cytotoxicity in the HaCaT cells. The decrease in cell viability was restored upon treatment with tart cherry extract (200 μg/mL) containing chlorogenic acid, quercetin, and kaempferol. Tart cherry inhibited the intracellular reactive oxygen species (ROS) responsible for the distinctive activations of the extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) in PM₁₀-treated HaCaT cells. Interestingly, tart cherry significantly inhibited the expression of apoptosis-related genes (B-Cell Lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax), and caspase-3) as regulated by the activation of transcription factor nuclear factor-kappa B (NF-κB). These results demonstrate that tart cherry is a medicinal food that blocks the mitochondrial pathway of apoptosis induced by PM₁₀ in human epidermal keratinocytes.

A Network Pharmacology-Based Approach to Investigating the Mechanisms of Fushen Granule Effects on Intestinal Barrier Injury in Chronic Renal Failure

Purpose

Fushen Granule (FSG) is a Chinese medicine prepared by doctors for treating patients with chronic renal failure, which is usually accompanied by gastrointestinal dysfunction. Here, we explore the protective effect of FSG on intestinal barrier injury in chronic renal failure through bioinformatic analysis and experimental verification.

Methods

In this study, information on the components and targets of FSG related to CRF is collected to construct and visualize protein-protein interaction networks and drug-compound-target networks using network pharmacological methods. DAVID is used to conduct gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Then, it is validated by in vitro experiments. In this study, the human intestinal epithelial (T84) cells are used and divided into four groups: control group, model group, FSG low-dose group, and FSG high-dose group. After the experiment, the activity of T84 cells is detected by a MTT assay, and the expressions of tight junction protein ZO-1, claudin-1, nuclear factor erythroid 2-related factor (Nrf2), heme oxygenase-1 (HO-1), malondialdehyde (MDA), and cyclooxygenase-2 (COX-2) are examined by immunofluorescence and/or western blotting.

Results

Eighty-six potential chronic renal failure-related targets are identified by FSG; among them, nine core genes are screened. Furthermore, GO enrichment analysis shows that the cancer-related signaling pathway, the PI3K-Akt signaling pathway, the HIF1 signaling pathway, and the TNF signaling pathway may play key roles in the treatment of CRF by FSG. The MTT method showed that FSG is not cytotoxic to uremic toxin-induced injured T84 cells. The results of immunofluorescence and WB indicate that compared with the control group, protein expressions level of ZO-1, claudin-1, and Nrf2 in T84 cells is decreased and protein expressions level of HO-1, MDA, and COX-2 is increased after urinary toxin treatment. Instead, compared with the model group, protein expressions level of ZO-1, claudin-1, and Nrf2 in T84 cells is increased and protein expressions level of HO-1, MDA, and COX-2 is decreased after FSG treatment.

Conclusion

FSG had a protective effect on urinary toxin-induced intestinal epithelial barrier injury in chronic renal failure, and its mechanism may be related to the upregulation of Nrf2/HO-1 signal transduction and the inhibition of tissue oxidative stress and inflammatory responses. Screening CRF targets and identifying the corresponding FSG components by network pharmacological methods is a practical strategy to explain the mechanism of FSG in improving gastrointestinal dysfunction in CRF.

Mitophagy Induced by Mitochondrial Function Damage in Chicken Kidney Exposed to Cr(VI)

Cr(VI) is a heavy metal environmental pollutant and carcinogen. Excessive Cr(VI) exposure injures kidneys. This study aimed to investigate mitophagy induced by mitochondrial function damage in chicken kidney exposed to Cr(VI). To explore the mechanism involved, we randomly divided 40 one-day-old Hy-line Brown cockerels into four groups, with each group exposed to different concentrations of Cr(VI), i.e., 0, 10, 30 and 50 mg kg^-1, which were orally administered daily for 45 days. Excessive Cr(VI) increased tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and chemokine (C-X-C motif) ligand 1(CXCL1) expression and decreased Ca²⁺-adenosine triphosphatase (Ca²⁺-ATPase), Mg²⁺-ATPase and Na⁺/k⁺-ATPase activities in chicken kidney. Furthermore, Cr(VI) significantly increased reactive oxygen species (ROS) production and induced mitochondrial membrane potential (MMP) collapse and typical autophagosome formation. With the increase of Cr(VI) concentration, the Parkin translocation, value of LC3-II increased and decreased the content of p62/SQSTM1 and the translocase of outer mitochondrial membrane 20 (TOMM20). In summary, our findings explicated that mitochondrial function damage and mitophagy-related indicators were related to Cr(VI) concentration in chicken kidney.

Sodium hydrosulfide alleviates dexamethasone-induced cell senescence and dysfunction through targeting the miR-22/sirt1 pathway in osteoblastic MC3T3-E1 cells

Glucocorticoid-induced osteoporosis is characterized by osteoblastic cell and microarchitecture dysfunction, as well as a loss of bone mass. Cell senescence contributes to the pathological process of osteoporosis and sodium hydrosulfide (NaHS) regulates the potent protective effects through delaying cell senescence. The aim of the present study was to investigate whether senescence could contribute to dexamethasone (Dex)-induced osteoblast impairment and to examine the effect of NaHS on Dex-induced cell senescence and damage. It was found that the levels of the senescence-associated markers, p53 and p21, were markedly increased in osteoblasts exposed to Dex. A p53 inhibitor reversed Dex-induced osteoblast injury, a process that was mitigated by NaHS administration through alleviating osteoblastic cell senescence. MicroRNA (miR)-22 blocked the impact of NaHS on Dex-induced osteoblast damage and senescence through targeting the regulation of Sirtuin 1 (sirt1) expression, as shown by the decreased cell viability and alkaline phosphatase activity, as well as an increased expression of p53 and p21. It was revealed that the sirt1 gene was the target of miR-22 in osteoblastic MC3T3-E1 cells through combining the results of dual luciferase reporter assays and reverse transcription-quantitative PCR, as well as western blot analyses. Silencing of sirt1 abolished the protective effect of NaHS against Dex-associated osteoblast senescence and injury. Taken together, the present study showed that NaHS prevents Dex-induced cell senescence and damage through targeting the miR-22/sirt1 pathway in osteoblastic MC3T3-E1 cells.

Nephroprotection through Modifying the Apoptotic TNF-α/ERK1/2/Bax Signaling Pathway and Oxidative Stress by Long-term Sodium Hydrosulfide Administration in Ovalbumin-induced Chronic Asthma

Asthma is one of the most common respiratory diseases in the world. Nevertheless, it is reported that inflammation induced by asthma is not only restricted to the lung and may cause damaging effects on remote organs. Therefore, this study was designed to investigate the beneficial effects of long-term sodium hydrosulfide (NaHS) administration on lung inflammation and oxidative stress markers to protect the kidney during chronic asthma. BALB/c mice were divided into three groups (n = 5-7): control, asthma and NaHS. Except the control group, sensitization and challenge were performed with ovalbumin. The NaHS group intraperitoneally received 14 μmol/kg NaHS 30 min before each challenge. 24 h after the last challenge, samples of bronchoalveolar lavage fluid (BALF), plasma, lung and kidney tissues were collected. NaHS administration significantly decreased total white blood cell count, percentages of eosinophils, neutrophils and macrophages and increased percentage of lymphocytes. Administration of NaHS considerably decreased the levels of BALF interleukin-13, plasma tumor necrosis factor-alpha (TNF-α), lung malondialdehyde (MDA) and lung phosphorylated nuclear factor-kappa B (p-NF-κB) expression and scores of peribronchial inflammatory cell infiltration, goblet cell hyperplasia and subepithelial fibrosis and increased the activity of lung superoxide dismutase (SOD). The MDA levels and expressions of p-ERK1/2 and Bax were decreased and SOD activity and expressions of Bcl-2 and p-Akt were significantly increased in kidney tissues by NaHS administration. Administration of NaHS decreased renal oxidative stress indices and reduced apoptosis by the inhibition of TNF-α/ERK1/2/Bax. Therefore, H₂S may have an essential role in renal protection during asthma.

Saturated hydrogen alleviates CCl4-induced acute kidney injury via JAK2/STAT3/p65 signaling

Objectives

This study assessed the protective effects of saturated hydrogen against CCl₄-induced acute kidney injury (AKI) in mice, and investigated signaling pathways activated by exposure to saturated hydrogen.

Methods

A mouse model of CCl₄-induced AKI was established; some mice were treated with saturated hydrogen. Levels of cystatin C and kidney injury molecule 1 were determined using enzyme-linked immunosorbent assays. Blood urea nitrogen and serum creatinine were measured on a fully automated biochemical analyzer. Interleukin-8, tumor necrosis factor-α, and interferon-γ in serum and kidney tissues were measured using enzyme-linked immunosorbent assays. Malondialdehyde, glutathione peroxidase, and superoxide dismutase in kidney tissues were measured using biochemical kits. Oxidative stress in kidney tissues was analyzed using nitrotyrosine staining. Expression levels of p-JAK2, p-STAT3, and p-p65 signal protein were assayed by immunohistochemistry and western blotting.

Results

Compared with untreated mice with CCl₄-induced AKI, mice that were treated with saturated hydrogen exhibited improved renal function and reduced oxidative stress. Moreover, expression levels of p-JAK2, p-STAT3, and p-p65 were significantly reduced in mice treated with saturated hydrogen, compared with expression levels in untreated mice.

Conclusions

Treatment with saturated hydrogen can reduce oxidative stress and inflammatory cytokine activation, potentially through inhibition of JAK2/STAT3/p65 signaling, thereby protecting against AKI.

Hydrogen Sulfide Attenuates High-Fat Diet-Induced Non-Alcoholic Fatty Liver Disease by Inhibiting Apoptosis and Promoting Autophagy via Reactive Oxygen Species/Phosphatidylinositol 3-Kinase/AKT/Mammalian Target of Rapamycin Signaling Pathway

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease worldwide. Hydrogen sulfide (H₂S) is involved in a wide range of physiological and pathological processes. Nevertheless, the mechanism of action of H₂S in NAFLD development has not been fully clarified. Here, the reduced level of H₂S was observed in liver cells treated with oleic acid (OA). Administration of H₂S increased the proliferation of OA-treated cells. The results showed that H₂S decreased apoptosis and promoted autophagy through reactive oxygen species (ROS)-mediated phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) cascade in OA-treated cells. In addition, administration of H₂S relieved high-fat diet (HFD)-induced NAFLD via inhibition of apoptosis and promotion of autophagy. These findings suggest that H₂S could ameliorate HFD-induced NAFLD by regulating apoptosis and autophagy through ROS/PI3K/AKT/mTOR signaling pathway. Novel H₂S-releasing donors may have therapeutic potential for the treatment of NAFLD.

Roles of Hydrogen Sulfide Donors in Common Kidney Diseases

Hydrogen sulfide (H2S) plays a key role in the regulation of physiological processes in mammals. The decline in H2S level has been reported in numerous renal disorders. In animal models of renal disorders, treatment with H2S donors could restore H2S levels and improve renal functions. H2S donors suppress renal dysfunction by regulating autophagy, apoptosis, oxidative stress, and inflammation through multiple signaling pathways, such as TRL4/NLRP3, AMP-activated protein kinase/mammalian target of rapamycin, transforming growth factor-β1/Smad3, extracellular signal-regulated protein kinases 1/2, mitogen-activated protein kinase, and nuclear factor kappa B. In this review, we summarize recent developments in the effects of H2S donors on the treatment of common renal diseases, including acute/chronic kidney disease, renal fibrosis, unilateral ureteral obstruction, glomerulosclerosis, diabetic nephropathy, hyperhomocysteinemia, drug-induced nephrotoxicity, metal-induced nephrotoxicity, and urolithiasis. Novel H2S donors can be designed and applied in the treatment of common renal diseases.

Polysulfide and Hydrogen Sulfide Ameliorate Cisplatin-Induced Nephrotoxicity and Renal Inflammation through Persulfidating STAT3 and IKKβ

Cisplatin, a widely used chemotherapy for the treatment of various tumors, is clinically limited due to its extensive nephrotoxicity. Inflammatory response in tubular cells is a driving force for cisplatin-induced nephrotoxicity. The plant-derived agents are widely used to relieve cisplatin-induced renal dysfunction in preclinical studies. Polysulfide and hydrogen sulfide (H₂S) are ubiquitously expressed in garlic, and both of them are documented as potential agents for preventing and treating inflammatory disorders. This study was designed to determine whether polysulfide and H₂S could attenuate cisplatin nephrotoxicity through suppression of inflammatory factors. In renal proximal tubular cells, we found that sodium tetrasulfide (Na₂S₄), a polysulfide donor, and sodium hydrosulfide (NaHS) and GYY4137, two H₂S donors, ameliorated cisplatin-caused renal toxicity through suppression of the massive production of inflammatory cytokines, including tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and cyclooxygenase-2 (COX-2). Mechanistically, the anti-inflammatory actions of Na₂S₄ and H₂S may be mediated by persulfidation of signal transducer and activator of transcription 3 (STAT3) and inhibitor kappa B kinase β (IKKβ), followed by decreased phosphorylation of STAT3 and IKKβ. Moreover, the nuclear translocation of nuclear transcription factor kappa B (NF-κB), and phosphorylation and degradation of nuclear factor kappa B inhibitor protein alpha (IκBα) induced by cisplatin, were also mitigated by both polysulfide and H₂S. In mice, after treatment with polysulfide and H₂S donors, cisplatin-associated renal dysfunction was strikingly ameliorated, as evidenced by measurement of serum blood urea nitrogen (BUN) and creatinine levels, renal morphology, and the expression of renal inflammatory factors. Our present work suggests that polysulfide and H₂S could afford protection against cisplatin nephrotoxicity, possibly via persulfidating STAT3 and IKKβ and inhibiting NF-κB-mediated inflammatory cascade. Our results might shed light on the potential benefits of garlic-derived polysulfide and H₂S in chemotherapy-induced renal damage.

Mitochondrial KATP channels contribute to the protective effects of hydrogen sulfide against impairment of central chemoreception of rat offspring exposed to maternal cigarette smoke

We previously reported that maternal cigarette smoke (CS) exposure resulted in impairment of central chemoreception and induced mitochondrial dysfunction in offspring parafacial respiratory group (pFRG), the kernel for mammalian central chemoreception. We also found that hydrogen sulfide (H₂S) could attenuate maternal CS exposure-induced impairment of central chemoreception in the rat offspring in vivo. Mitochondrial ATP sensitive potassium (mitoK_ATP) channel has been reported to play a significant role in mitochondrial functions and protect against apoptosis in neurons. Thus, we hypothesize here that mitoK_ATP channel plays a role in the protective effects of H₂S on neonatal central chemoreception in maternal CS-exposed rats. Our findings revealed that pretreatment with NaHS (donor of H₂S, 22.4mM) reversed the central chemosensitivity decreased by maternal CS exposure, and also inhibited cell apoptosis in offspring pFRG, however, 5-HD (blocker of mitoK_ATP channels, 19mM) attenuated the protective effects of NaHS. In addition, NaHS declined pro-apoptotic proteins related to mitochondrial pathway apoptosis in CS rat offspring pFRG, such as Bax, Cytochrome C, caspase9 and caspase3. NaHS or 5-HD alone had no significant effect on above indexes. These results suggest that mitoK_ATP channels play an important role in the protective effect of H₂S against impairment of central chemoreception via anti-apoptosis in pFRG of rat offspring exposed to maternal CS.

Zinc exerts its renal protection effect on arsenic-exposed common carp: A signaling network comprising Nrf2, NF-κB and MAPK pathways

Epidemiological and laboratory investigations have extensively indicated that arsenic exposure accounts for several kidney diseases. Zinc has been suggested as a possible natural preventive and therapeutic agent. This study is designed to explore the beneficial effect of zinc supplementation against arsenic-induced renal toxicity in common carp, and the results point to signaling pathway possibly compromised. In the present study, renal injury was induced in common carp by waterborne exposure to arsenic (2.83 mg/L) for 30 days, and zinc (1 mg/L) was simultaneously supplemented. First, the arsenic-exposed fish showed histological and functional renal alterations (indicated by hematoxylin-eosin staining, biochemical indexes and a TUNEL assay). Moreover, as a reactive oxygen species (ROS) stimulant, arsenic was found to induce oxidative toxicity as determined by increased renal ROS, malondialdehyde, protein carbonyl and 8-hydroxydeoxyguanosine levels. When antioxidant-mediation attempts (through superoxide dismutase and glutathione)-mediated to restore homeostasis failed and ROS increased to extreme levels, inflammation (indicated by elevated inducible nitric oxide synthetase, tumor necrosis factor-alpha and interleukins levels) and apoptosis (through both mitochondrial- and death receptor-dependent pathways) were triggered. However, abnormalities in the upstream mediators Nrf2, NF-κB and MAPK were significantly ameliorated and blocked by treatment with zinc. In conclusion, zinc exerts a substantial protective effect against arsenic-triggered subchronic renal injury in common carp via the amelioration of oxidative stress, suppression of apoptosis and reduced inflammation through Nrf2, NF-κB and MAPK signaling.

Erlotinib can halt adenine induced nephrotoxicity in mice through modulating ERK1/2, STAT3, p53 and apoptotic pathways

Renal fibrosis is a failed regenerative process that facilitates chronic kidney disease progression. The current study was designed to study the effect of erlotinib, a receptor tyrosine kinase inhibitor, on the progression of renal fibrosis. The study included four groups of mice: control group; adenine group: received adenine (0.2% w/w) daily with food for 4 weeks; erlotinib group: received 80 mg/kg/day erlotinib orally (6 ml/kg/day, 1.3% w/v suspension in normal saline 0.9%) for 4 weeks; adenine + erlotinib group: received adenine and erlotinib concurrently. Kidney function and antioxidant biomarkers were measured. Renal expression of Bcl2 and p53 and histopathological changes (tubular injury and renal fibrosis) were scored. Renal tissue levels of transforming growth factor-β₁, p-ERK1/2 and p-STAT3 were measured. Results obtained showed significant decrease (P < 0.001) in serum creatinine, urea and uric acid in erlotinib + adenine group. Level of malondialdehyde was decreased significantly (P < 0.001) while reduced glutathione and catalase levels were increased (P < 0.01) by erlotinib concurrent administration. Erlotinib markedly reduced fibrosis and tubular injury and decreased TGF-β1, p-ERK1/2 and p-STAT3 (P < 0.5). In addition, expression level of Bcl-2 was elevated (P < 0.001) while that of p53-was reduced compared to adenine alone. Erlotinib can attenuate renal fibrosis development and progression through anti-fibrotic, antioxidant and anti-apoptotic pathways.

Tubular β-catenin and FoxO3 interactions protect in chronic kidney disease

The Wnt/β-catenin signaling pathway plays an important role in renal development and is reexpressed in the injured kidney and other organs. β-Catenin signaling is protective in acute kidney injury (AKI) through actions on the proximal tubule, but the current dogma is that Wnt/β-catenin signaling promotes fibrosis and development of chronic kidney disease (CKD). As the role of proximal tubular β-catenin signaling in CKD remains unclear, we genetically stabilized (i.e., activated) β-catenin specifically in murine proximal tubules. Mice with increased tubular β-catenin signaling were protected in 2 murine models of AKI to CKD progression. Oxidative stress, a common feature of CKD, reduced the conventional T cell factor/lymphoid enhancer factor-dependent β-catenin signaling and augmented FoxO3-dependent activity in proximal tubule cells in vitro and in vivo. The protective effect of proximal tubular β-catenin in renal injury required the presence of FoxO3 in vivo. Furthermore, we identified cystathionine γ-lyase as a potentially novel transcriptional target of β-catenin/FoxO3 interactions in the proximal tubule. Thus, our studies overturned the conventional dogma about β-catenin signaling and CKD by showing a protective effect of proximal tubule β-catenin in CKD and identified a potentially new transcriptional target of β-catenin/FoxO3 signaling that has therapeutic potential for CKD.

Quercetin alleviates lipopolysaccharide-induced inflammatory responses by up-regulation miR-124 in human renal tubular epithelial cell line HK-2

Chronic kidney disease (CKD) is a persistent kidney structural and functional disorder. Quercetin is one of active extracted flavonoids and has protective effects. Therefore, we proposed to survey the effect of Quercetin on CKD. HK-2 cells were preprocessed by Quercetin and then irritated with lipopolysaccharide (LPS). CCK-8 assay and flow cytometry were utilized to test viability and apoptosis. ELISA assay was utilized to estimate the IL-6 and TNF-α secretion. Western blot was performed to examine the expression of apoptosis and inflammation-associated mediators. After that HK-2 cells were transfected by miR-124 inhibitor. And the above-mentioned parameters were reassessed. LPS stimulated apoptosis and declined viability in HK-2 cells. Additionally, LPS stimulated inflammatory responses. Meanwhile, Quercetin attenuated LPS-stimulated apoptosis, production of IL-6, and TNF-α in experimental cells. Subsequently, MyD88 and miR-124 expression was elevated by LPS and alleviated by Quercetin. Finally, Quercetin exerted its protective function through NF-κB pathway via up-regulating miR-124. Our data demonstrated that Quercetin reduced apoptosis and inflammation stimulated by LPS in HK-2 cells. Moreover, Quercetin alleviated LPS-stimulated injury by up-regulating miR-124.

Hydrogen sulfide renal protective effects: possible link between hydrogen sulfide and endogenous carbon monoxide in a rat model of renal injury

Hydrogen sulfide (H2S), along with nitric oxide (NO) and carbon monoxide (CO), proved to have renoprotective effects in various renal diseases. Therefore, this study investigated the renoprotective effect of H2S, in a renal injury model, and its crosstalk with other gasotransmitters such as CO. Thirty-two adult rats were divided into four groups: control, gentamicin (GEN)-treated, GEN + sodium hydrosulfide (NaHS), and GEN + NaHS + zinc protoporphyrin (ZnPP) groups. GEN was used to induce renal injury, NaHS is a water-soluble H2S, and ZnPP is a selective heme oxygenase-1 (HO-1) inhibitor used to inhibit CO synthesis in vivo. NaHS improved kidney functions in the GEN group as evidenced by significantly lower levels of renal injury markers: serum urea, creatinine, uric acid, urinary albumin excretion, and urinary albumin/creatinine. Moreover, NaHS administration to the GEN-treated group significantly lowered renal levels of NO and tumor necrosis factor-α with an increase in total antioxidant, HO-1, and interleukin-10 levels. Furthermore, NaHS administration downregulated the GEN-induced overexpression of the renal inducible nitric oxide synthase (iNOS) and upregulated the suppression of endothelial nitric oxide synthase (eNOS) with improvement in the histological examination and periodic acid Schiff (PAS) staining. However, this improvement in kidney function produced by NaHS was reduced by combination with ZnPP but still improved as compared with the GEN-treated group. The renoprotective effects of H2S can be through its effects on renal tissue antioxidants, pro-inflammatory and anti-inflammatory cytokines, and expression of eNOS and iNOS which can be partially dependent on CO pathway via induction of HO-1 enzyme.

Hydrogen sulfide promotes lipopolysaccharide-induced apoptosis of osteoblasts by inhibiting the AKT/NF-κB signaling pathway

Apoptosis of osteoblasts plays a crucial role in osteomyelitis. Hydrogen sulfide (H₂S) levels are increased in the pathophysiological processes of osteomyelitis. However, the effect of H₂S on the apoptosis of osteoblasts remains unclear. To investigate the specific role of H₂S in osteoblast apoptosis, MC3T3-E1 and hFOB cells were treated with NaHS or Na₂S, a donor of H₂S, and lipopolysaccharide (LPS), during osteomyelitis. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, flow cytometry analysis, western blotting, immunofluorescence, polymerase chain reaction, and Alizarin red staining were performed to examine the effects of H₂S on osteoblast cell apoptosis, cell osteogenic differentiation, and AKT kinase (AKT)/nuclear factor kappa B (NF-κB) signaling. Hydrogen sulfide increased cell apoptosis, and inhibited the proliferation and osteogenic differentiation of osteoblast cells impaired by LPS. H₂S increased apoptosis through upregulation of the FAS ligand (FASL) signaling pathway. H₂S-induced apoptosis was alleviated using a FAS/FASL signaling pathway inhibitor. Treatment with NaHS also increased cell apoptosis by downregulating AKT/NF-κB signaling. In addition, treatment with an AKT signaling pathway activator decreased apoptosis and reversed the inhibitory effects of H₂S on osteogenic differentiation. Hydrogen sulfide promotes LPS-induced apoptosis of osteoblast cells by inhibiting AKT/NF-κB signaling.

Elastase-triggered H2S delivery from polymer hydrogels

We report an elastase-responsive, H2S-releasing hydrogel prepared by covalently crosslinking a mixture of carboxymethylcellulose and poly(ethylene glycol) with an elastase-degradable peptide functionalized with an H2S-releasing S-aroylthiooxime (SATO) unit. Addition of elastase triggered a gel-to-sol transition, which exposed SATOs, leading to more and longer H2S release compared to untriggered gels.

H2S alleviates renal injury and fibrosis in response to unilateral ureteral obstruction by regulating macrophage infiltration via inhibition of NLRP3 signaling

Renal fibrosis is a key pathological feature in chronic kidney diseases (CKDs). Dysregulation of hydrogen sulfide (H₂S) homeostasis is implicated in the pathogenesis of CKDs. Here, C57/BL6 mice were allocated to Sham and unilateral ureteral obstruction (UUO) groups, which were treated with NaHS or NLRP3 inflammasome inhibitor 16673-34-0 for 3-14 days. UUO mice displayed downregulation of H₂S production and increased macrophage infiltration in obstructed kidneys. H₂S donor NaHS treatment attenuated renal damage and fibrosis and inhibited M1 and M2 macrophage infiltration. NLPR3 inflammasome was activated and levels of phosphorylated nuclear factor κB (NF-κB) p65 subunit, phosphorylated signal transducer and activator of transcription 6 (STAT6) and interleukin (IL)-4 protein were increased in the kidneys after UUO. NLRP3 inhibitor inactivated NF-κB and IL-4/STAT6 signaling, suppressed M1 and M2 macrophage infiltration and attenuated renal damage and fibrosis in UUO mice. NaHS treatment also suppressed NLRP3, NF-κB and IL-4/STAT6 activation in the obstructed kidneys. In conclusion, the therapeutic effects of H₂S on UUO-induced renal injury and fibrosis are at least in part by inhibition of M1 and M2 macrophage infiltration. H₂S suppresses NLRP3 activation and subsequently inactivates NF-κB and IL-4/STAT6 signaling, which may contribute to the anti-inflammatory and anti-fibrotic effects of H₂S.

Antioxidant, anti-inflammatory, and antiapoptotic effects of virgin coconut oil against antibiotic drug gentamicin-induced nephrotoxicity via the suppression of oxidative stress and modulation of iNOS/NF-ĸB/caspase-3 signaling pathway in Wistar rats

Gentamicin is an effective antibiotic against severe infections; however, its major side effect is oxidative nephrotoxicity. We explored whether virgin coconut oil (VCO) could mitigate gentamicin-induced nephrotoxicity. Rats were fed with VCO-supplemented diet for 16 days against renal toxicity induced by gentamicin (100 mg/kg bw, ip) from Day 11 to 16. Gentamicin caused marked elevated serum urea, uric acid, and creatinine levels, followed by considerable depletion in renal antioxidant enzymes, glutathione (GSH), while the malondialdehyde (MDA) level increased significantly. It significantly increased renal cytokines and nitric oxide (NO) levels, confirmed by renal histopathology. The expression of inducible nitric oxide synthase (iNOS), nuclear factor-kappa B (NF-ĸB), and caspase-3 was prominently increased. VCO-supplemented diet significantly modulated the levels of biochemical indices, downregulated the expression of NO, iNOS, NF-ĸB, caspase-3, cytokines, and alleviated histopathological lesions. VCO protects against gentamicin-induced nephrotoxicity; thus, it could be a promising dietary supplement for patients undergoing gentamicin treatment. PRACTICAL APPLICATIONS: Gentamicin is an efficacious clinical antibiotic used against severe infections; however, the robust body of evidence indicates that the nephrotoxic side effect constrained its use. Virgin coconut oil (VCO) is an edible oil with growing human consumption and pharmacological effects. Our study has reported herein, for the first time, that VCO diet prevented the nephrotoxicity of gentamicin. Dietary supplementation of this oil could be beneficial in alleviating the nephrotoxic side effect of gentamicin in patients.

Annexin A2 upregulation protects human retinal endothelial cells from oxygen-glucose deprivation injury by activating autophagy

Retinal neovascularization is a common pathological change in multiple diseases of the eyes and the upregulation of annexin A2 (A2) under a hypoxic and ischemic microenvironment has been demonstrated to be a key factor in the pathological process. However, the underlying mechanism by which A2 regulates retinal neovascularization remains unclear. In the present study, oxygen-glucose deprivation (OGD) was used to mimic the hypoxic and ischemic microenvironment, to observe the role of A2 in retinal neovascularization regulation by focusing on autophagy. The results showed that OGD treatment significantly increased the mRNA and protein levels of A2 in human retinal endothelial cells (HRECs), which was dependent on activation of hypoxia inducible factor (HIF)-1α signaling. The OGD-induced activation of autophagy was attenuated when A2 was silenced, but increased when A2 was overexpressed, suggesting that A2 upregulation contributed to OGD-induced cell autophagy activation. Furthermore, knockdown of A2 decreased cell viability and promoted cell apoptosis under OGD conditions. Overexpression of A2 increased cell viability and reduced cell apoptosis under OGD conditions, and inhibiting autophagy using an inhibitor, reversed these changes, suggesting that upregulation of A2 by OGD serves a cytoprotective role by inducing cell autophagy in HRECs. Taken together, the results of the present study suggested that promoting retinal endothelial cell survival by autophagy activation via the HIF-1α signaling pathway in a hypoxic and ischemic microenvironment may underlie the mechanism by which A2 regulates retinal neovascularization. The present study is the first study to demonstrate the novel role of A2 during retinal neovascularization under pathological conditions, to the best of our knowledge. Therefore, A2 may serve as a potential therapeutic target for treating neovascularization-associated conditions of the eye.